1. Field of the Invention
The present invention relates to a piping joint structure in an automotive air-conditioning unit for use on a motor vehicle such as an automobile.
2. Description of the Related Art
As shown in FIG. 10 of the accompanying drawings, one conventional piping joint structure in an automotive air-conditioning unit has a block joint 2 disposed in a through hole defined in a dashboard panel 1 which divides an engine compartment 9a and a passenger's compartment 9b from each other in an automobile. To the block joint 2, there are fastened joint members 3 in the passenger's compartment 9b and joint members 4 in the engine compartment 9a by screws (not shown). A heater unit 6 is connected to pipes 5 exposed in the passenger's compartment 9b, and a blower 8 is coupled to the heater unit 6 through a maintenance lid 7.
The illustrated conventional piping joint structure needs to have a heat-insulating member covered around the pipes 5, which interconnect the heat unit 6 and the joint members 3, to prevent water droplets from being deposited on outer surfaces of the pipes 5 due to condensation. As a consequence, the conventional piping joint structure is made up of a relatively large number of parts.
Since the joint members 3 and the joint members 4 which are connected respectively opposite sides of the block joint 2 are required, the number of parts of the conventional piping joint structure is also relatively large, resulting in a large cost required to manufacture the conventional piping joint structure.
When an air-conditioning unit is to be assembled, the joint members 3 and the joint members 4 have to be fastened to the block joint 2 by screws. For maintenance of the air-conditioning unit, it is necessary to remove the joint members 3, which are installed in a relatively small space, from the block joint 2. Consequently, the processes of assembling the air-conditioning unit and servicing the air-conditioning unit for maintenance are complex and time-consuming.